Press-fit terminals that are press-fitted for use into through holes of printed circuit boards are conventionally known, and, as described in JP 2004-127610A, for example, are provided with a pressure contact part having springiness on one end side of a terminal fitting that is plated after being punched out from a metal plate and with a connection part configured to be connected to a partner side member on the other end of the terminal fitting. By then press-fitting the pressure contact part into a through hole of a circuit board, the pressure contact part is electrically connected through pressure contact to a conductor exposed inside the through hole.
Incidentally, as also described in JP 2004-127610A, the press-fit terminal is formed by post-plating a press-cut surface constituting the pressure contact part after press punching a metal plate. On the one end side of the terminal fitting, an open hole is then punched out in a central portion to form a pair of arch-shaped pressure contact parts, and springiness is provided by the pair of pressure contact parts being made elastically deformable in the plate width direction.
However, given that it is difficult to secure sufficient flexure with a pair of pressure contact parts that are made arch-shaped by punching out an open hole in a central portion, increasing the insertion force of the pressure contact parts on the through hole is unavoidable, and runs the risk of the pressure contact parts scraping the inner surface of the through hole and producing metal filings. Also, given that the pair of arch-shaped pressure contact parts are formed by punching out an open hole in a central portion, a press-fit terminal having this shape cannot be easily constituted using a very narrow terminal fitting, and it is difficult to cope with the increasing densification of printed circuit boards. Furthermore, given that the pressure contact parts are constituted by the press-cut surface formed at the time of the press punching process, post-plating is essential, resulting in an unavoidable increase in costs.
In view of this, the inventor proposed a press-fit terminal in which the pressure contact parts are formed using the plating surface of a metal plate by forming a slit that extends in the length direction in a central portion of the pressure contact parts, and causing both sides of this slit to project on opposite sides to each other, as initially shown in FIG. 15 of JP 2016-27536A. According to this press-fit terminal, given that springiness is provided by making the pressure contact parts readily elastically deformable in the plate thickness direction, the insertion force of the pressure contact parts on the through hole can be reduced, and the problem of the pressure contact parts scraping the inner surface of the through hole can also be reduced, compared with the case where the pressure contact parts are elastically deformable in the plate width direction. Also, given that the pressure contact parts are formed by a slit that extends in the length direction through a central portion of the terminal, a press-fit terminal having the above shape can also be constituted using a very narrow terminal fitting, and it also becomes possible to cope with the increasing densification of printed circuit boards. Furthermore, given that the pressure contact parts are not constituted by a press-cut surface formed at the time of a press punching process, post-plating is not required, enabling costs to be reduced.
However, even though the pressure contact parts are not constituted by a press-cut surface formed at the time of a press punching process, it is conceivable that the plating on the surface of the pressure contact parts could possibly be damaged at the time of providing the slit when forming this press-fit terminal using a terminal fitting having an even smaller width dimension. Hence, there is still room for improvement, and further development on an improved press-fit terminal has been progressing.
JP 2004-127610A and JP 2016-27536A are examples of related art.